Developing chamber for thin layer chromatograms



March 17,1970 J. PLIML Em 3,501,008

DEVELOPING CHAMBER FOR THIN LAYER CHROMATOGRAMS Filed March 5, 1969 2 Sheets-Sheet 1 W INVENTORS, 77H film; fia f fgg 7734/6 March 17, 1970 J. PLIML m DEVELOPING CHAMBER FOR THIN LAYER OHROMATOGRAMS Filed March a, 1969 2 Sheets-Sheet I A INVENTORS far/177326 772m? United States Patent 3,501,008 DEVELOPING CHAMBER FOR THIN LAYER CHROMATOGRAMS Jifi Pliml and Jan Simonides, Prague, 'Czechoslovakia,

and Frantisek Plzzik, Ehikon-Lucerne, Switzerland, assignors to Ceskoslovenska akademie ved, Prague, Czechoslovakia Filed Mar. 3, 1969, Ser. No. 804,064 Claims priority, application Czechoslovakia, Mar. 4, 1968, 1,706/68 Int. Cl. B01d 15/08 US. Cl. 210-198 6 Claims ABSTRACT OF THE DISCLOSURE A developing chamber for chromatograms includes two glass plates which form the closely spaced front and back walls of the chamber, and another plate forming the top wall, the chamber bottom being open. The front and back plates are sealed to each other by interengaged, integral, upright rails and grooves, and the chromatogram is clamped in position between the back wall and an elongated, wedge-shaped ridge projecting from the top wall into the chamber cavity and a row of rounded projections on the front wall near the open end of the chamber cavity.

This invention relates to chromatography, and particularly to a developing chamber for thin layer chromatograms.

As is well known, the chamber in which a thin layer chromatogram is developed should be uniformly saturated with vapors of the solvent system employed for de velopment, and the migration rate of a substance spotted on the absorbent layer of the chromatogram can be significantly different in portions of the chromatogram exposed to different concentrations of solvent vapor during development.

It has been found heretofore that uniform vapor saturation is readily maintained in narrow developing chambers in which the distance between the chromatogram and the opposite chamber wall is at a minimum, and not greater than 3 millimeters, if the narrow edges of the chamber are adequately sealed. Permanent sealing systerns for narrow developing chambers were rather costly and complex heretofore, and the simple and effective expedient of coating the edges of a developing chamber with molten wax and solidifying the wax consumes relatively I much time and effort.

A primary object of this invention is the provision of a narrow developing chamber for chromatograms which is equipped with a permanent sealing system ensuring uniform solvent vapor saturation throughout the chamber cavity, yet simple and inexpensive. More specifically, the invention aims at providing a narrow developing chamber for chromatograms of the type disclosed in Patent No. 3,409,136.

The developing chamber of the invention has front and back walls having respective oppositely spaced faces which define the chamber cavity therebetween, the thickness of the cavity between the faces being a small fraction of the major cavity dimensions of length and width. Two rails elongated in the direction of one of these major dimensions are each offset from the cavity in the direction of the other major dimension away from the other rail. Each rail projects from one of the aforementioned walls and is releasably received in a recess of the other wall in conforming engagement.

The cavity is closed in one direction of said one major dimension by a top wall from which an elongated ridge 3,501,008 Patented Mar. 17, 1970 projects into the cavity in conforming engagement with the face of the front wall while defining a gap with the face of the back wall, the spacing of the ridge from the back wall across the gap being smaller than the thickness of the cavity. When the gap tapers in a direction to ward the front wall, a chromatogram of the patent cited above can be clamped fast in the gap by its own resiliency.

The narrow edges of the cavity transverse to the top wall are particularly closely sealed if respective portions of the principal back and front walls make area contact with each other on either side of the cavity intermediate the cavity and the rails, and on the side of the rails offset from the latter in a direction away from the cavity.

The sealing of the narrow cavity edge alongthe top wall is most effective if the length of the ridge is substantially equal to the other major dimension of the cavity portion receiving the ridge. The ridge holds the chromatogram against the back wall and is assisted in this function by projections on the front wall remote from the top wall whose spacing from the back wall is approximately equal to the width of the gap referred to above.

Other features, additional objects, and many of the attendant advantages of this invention will readily become apparent from the following description of the preferred embodiment and of modifications of the same when considered in connection with the appended drawing in which:

FIG. 1 shows a partly opened developing chamber of the invention in front elevation and in the operating position;

FIG. 2 is a bottom plan view of the chamber of FIG. 1 in the closed condition;

FIG. 3 shows a solvent trough for use with the chamber of FIG. 1 in top plan view;

FIGS. 4 and 5 show respective modifications of a portion of the chamber in enlarged fragmentary views corresponding to that of FIG. 2;

FIG. 6 "shows the chamber of FIG. 1 in fragmentary side-elevational section on the line VIVI in the loading position; and

FIG. 7 shows a modification of the device of FIG. 6.

Referring now to the drawing in detail, and initially to FIGS. 1, 2, and 6, there is seen a glass development chamber for thin layer chromatograms which consists of a rectangular front wall 1, a rectangular back Wall 2, and a top wall 3. Two parallel rails 6, approximately square in cross section, integrally project from the otherwise fiat inner face of the back wall 2 spacedly adjacent two opposite edges of the inner face into mating grooves 16 in the inner face of the front wall 1.

The latter also has a shallow depression 10 separated from the grooves 16 by narrow ribs 11, and constituting the cavity of the development chamber. The walls 1 and 2 are of uniform cross section so that the rails 6 extend over the entire length of the back wall 2, and the grooves 16 and ribs 11 over the full length of the front wall 1. The walls 1, 2 are equal in length.

The chamber cavity 10 is normally closed at one end by the top wall 3 which is a flat and narrow glass plate carrying a wedge shaped ridge 9 which extends longitudinally of the top wall over a distance equal to the width of the chamber cavity 10. When the top wall 3 is placed on the superposed front and back walls 1, 2 the ridge 9 extends into the cavity 10. As is best seen in FIG. 6, a fiat face of the ridge 9 makes area contact with the front wall 1 in the cavity 10 while an opposite obliquely sloping face of the ridge is sufficiently spaced from the fiat face of the back wall 2 to accommodate the thickness of a chromatogram 4.

The bottom end of the chamber cavity 10 remains open, and the bottom end of the chamber is received during development in a loosely conforming recess 12 of a sol- 3 vent trough 13 shown in FIG. 3. The trough illustrated s a unitary piece of glass. Rounded integral projections are spaced in a row across the width of the front wall l near the open bottom of the chamber cavity 10.

A chromatogram is developed in the aforedescribed apparatus as follows:

The. back wall 2 is placed on a horizontal surface, inner face up, and a chromatogram 4, which may be of the type described in the cited patent, is laid on the exposed face of the wall 2. The top wall 3 is placed against the top edge of the back wall 2 as shown in FIG. 6, and the position of the chromatogram 4 is adjusted as may be needed to bring the top edge of the chromatogram into the gap between the ridge 9 and the back wall. The width of that gap tapers toward the front wall 3, and is seiected in such a manner that the edge of the chromatogram is clamped between the ridge 9 and the back wall 2, thereby sealing the gap. The front wall 1 is placed on top of the wall 2, and the chromatogram 4 is entirely received within the cavity 10. The ribs 11 as well as similar integral ribs 14 between the grooves 16 and the lateral edges of the front wall 1 make area contact with the inner face of the back wall 2.

A rubber band (not shown) is slipped about the front and back walls 1, 2 to hold them in the assembled condition, and the assembled chamber is turned into the operative position seen in FIG. 1 in which the top wall 3 is held in place partly by gravity, and partly by the resiliency of the chromatogram 4 which in turn is wedged between the ridge 9 and the back wall 2, and between the back wall 2 and the projections 5 whose spacing from the back wall 2 corresponds to the width of the gap near the ridge 9. The bottom of the chamber is then immersed in solvent in the recess 12 of the trough 13.

The chamber cavity is tightly sealed from the ambient atmosphere during development along its upright edges by the ribs 11, 14'engaging the inner face of the back wall, and by the rails 6 conformingly received in the grooves 16. Solvent vapor also cannot escape from the top of the cavity 10 which is sealed by the edge of the chromatogram 4, and air cannot enter.

While rails 6 of square or rectangular section are provided on the back wall 2 by molding and grinding at lowest cost, the cross sectional shape of the rails and of the conforming grooves in the front wall 1 may be modified without departing from the spirit of the invention.

The rail -7 illustrated in FIG. 4 has one side face adjacent the rail 11 which is perpendicular to the interface of the top and bottom walls 1, 2, whereas the other side face is obliquely inclined to the interface, and the outer rail 14 of the front wall 1 is comformingly shaped. The rail 8 shown in FIG. 5 has two side faces obliquely inclined in opposite directions so as to form a dovetail joint with the conforming rails 11, 14' of the front wall 1. Whereas the square rails 6 permit the front wall 1 to be slid longitudinally over the back wall 2 or moved at right angles to the inner face of the wall 2 when the chamber is to opened or closed, the modified chambers partly seen in FIGS. 4 and 5 are less conveniently opened and closed, but do not rely entirely on the aforementioned rubber band for holding" them assembled.

FIG. 7 shows yet another modification of a developing chamber otherwise identical with the apparatus seen in FIGS. 1-3 and 6, in which the top wall 3 is integral with the back wall 2. The aforedescribed operation of the chamber is modified in the device of FIG. 7 to the extent that the chromatogram 4 is pushed into the inwardly tapering gap between the ridge 9 and the back wall 2 until it is clamped with a force sutficient to hold the chromatogram in position in the upright chamber during development, but the modified embodiment seen in FIG. 7 does not employ the chromatogram itself as a sealing element.

The projections 5 on the front wall 1 hold the lower edge portion of the chromatogram against the back Wall 2 as the top edge is held by the ridge 9, and a uniform spacing is thereby maintained between the absorbent layer on the exposed face of the carrier sheet of the chromatogram and the opposite face of the front wall 1 in the cavity 10. This spacing is preferably close to two millimeters, and may vary between one and three millimeters.

Obviously, the positions of various elements in the illustrated apparatus may be interchanged without departing from the spirit of the invention, and without significantly afiecting the operation of the device. Thus, one or both rails 6 may project from the back wall 2 into corresponding grooves of the front wall, and the cavity 10 may be provided in the inner face of the back wall or extend into the inner faces of both principal walls 1, 2. The top wall 3 may be integral with the front wall 1, and numerous other permutations and variations of the illustrated elements and of their positions will readily suggest themselves to those skilled in the art.

Glass is the preferred material of construction at this time, but stainless steel or other corrosion resistant material may be used at least for some elements of the apparatus where breaking resistance is more important than transparency, and polymethyl methacrylate has been used successfully with solvent systems which do not attack the plastic.

We claim:

1. A developing chamber for thin-layer chromatograms comprising:

(a) a front wall;

(b) a back Wall, said two walls constituting the principal walls of said chamber and having respective oppositely spaced faces defining a cavity therebetween, the thickness of said cavity between said faces being a small fraction of the major dimensions of length and width of said cavity;

(0) two rails elongated in the direction of one of said major dimensions and each offset from said cavity in the direction of the other major dimension away from the other rail,

(1) each rail projecting from one of said walls and being releasably received in a recess of the other wall in conforming engagement;

(d) a top wall closing said cavity in one direction of said one major dimension; and

(e) an elongated ridge projecting from said top wall into said cavity in conforming engagement with said face of said front wall and defining a gap with said face of the back wall, the spacing of said ridge from said back wall across said gap being smaller than the thickness of said cavity.

2. A chamber as set forth in claim 1, wherein said gap tapers in a direction toward said front wall.

3. A chamber as set forth in claim 1, wherein respective portions of said principal walls intermediate said cavity and said rails on either side of said cavity make area contact with each other.

4. A chamber as set forth in claim 3, wherein respective portions of said principal walls offset from each of said rails in a direction away from said cavity make area contact with each other.

5. A chamber as set forth in claim 1, wherein the length of said ridge is substantially equal to said other major dimension of the portion of said cavity receiving said ridge.

6. A chamber as set forth in claim 1, further comprising a plurality of spaced projections on said face of the front wall remote from said top wall, the spacing of said projections from said back wall being approximately equal to the width of said gap between said ridge and said back wall.

References Cited UNITED STATES PATENTS 5/1967 Przybylowicz et al. 210-498 4/1968 Jetfreys et al. 210-198 JAMES L. =DECESARE, Primary Examiner 

